Zoology (Scholarly Publications)http://hdl.handle.net/2262/102
Zoology (Scholarly Publications)Tue, 03 Mar 2015 20:21:37 GMT2015-03-03T20:21:37ZPlasma cytokines, chemokines and cellular immune responses in preschool Nigerian children infected with Plasmodium falciparumhttp://hdl.handle.net/2262/72748
Plasma cytokines, chemokines and cellular immune responses in preschool Nigerian children infected with Plasmodium falciparum
HOLLAND, CELIA
BACKGROUND:
Malaria is a major cause of morbidity and mortality worldwide with over one million deaths annually, particularly in children under five years. This study was the first to examine plasma cytokines, chemokines and cellular immune responses in pre-school Nigerian children infected with Plasmodium falciparum from four semi-urban villages near Ile-Ife, Osun State, Nigeria.
METHODS:
Blood was obtained from 231 children (aged 39-73 months) who were classified according to mean P. falciparum density per μl of blood (uninfected (n = 89), low density (<1,000, n = 51), medium density (1,000-10,000, n = 65) and high density (>10,000, n = 22)). IL-12p70, IL-10, Nitric oxide, IFN-γ, TNF, IL-17, IL-4 and TGF-β, C-C chemokine RANTES, MMP-8 and TIMP-1 were measured in plasma. Peripheral blood mononuclear cells were obtained and examined markers of innate immune cells (CD14, CD36, CD56, CD54, CD11c AND HLA-DR). T-cell sub-populations (CD4, CD3 and γδTCR) were intracellularly stained for IL-10, IFN-γ and TNF following polyclonal stimulation or stimulated with malaria parasites. Ascaris lumbricoides was endemic in these villages and all data were analysed taking into account the potential impact of bystander helminth infection. All data were analysed using SPSS 15 for windows and in all tests, p <0.05 was deemed significant.
RESULTS:
The level of P. falciparum parasitaemia was positively associated with plasma IL-10 and negatively associated with IL-12p70. The percentage of monocytes was significantly decreased in malaria-infected individuals while malaria parasitaemia was positively associated with increasing percentages of CD54+, CD11c+ and CD56+ cell populations. No association was observed in cytokine expression in mitogen-activated T-cell populations between groups and no malaria specific immune responses were detected. Although A. lumbricoides is endemic in these villages, an analysis of the data showed no impact of this helminth infection on P. falciparum parasitaemia or on immune responses associated with P. falciparum infection.
CONCLUSIONS:
These findings indicate that Nigerian children infected with P. falciparum exhibit immune responses associated with active malaria infection and these responses were positively associated with increased P. falciparum parasitaemia.
PUBLISHED
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2262/727482013-01-01T00:00:00ZAscaris co-infection does not alter malaria-induced anaemia in a cohort of Nigerian preschool children.http://hdl.handle.net/2262/72745
Ascaris co-infection does not alter malaria-induced anaemia in a cohort of Nigerian preschool children.
HOLLAND, CELIA
BACKGROUND:
Co-infection with malaria and intestinal parasites such as Ascaris lumbricoides is common. Malaria parasites induce a pro-inflammatory immune response that contributes to the pathogenic sequelae, such as malarial anaemia, that occur in malaria infection. Ascaris is known to create an anti-inflammatory immune environment which could, in theory, counteract the anti-malarial inflammatory immune response, minimizing the severity of malarial anaemia. This study examined whether Ascaris co-infection can minimize the severity of malarial anaemia.
METHODS:
Data from a randomized controlled trial on the effect of antihelminthic treatment in Nigerian preschool-aged (6-59 months) children conducted in 2006-2007 were analysed to examine the effect of malaria and Ascaris co-infection on anaemia severity. Children were enrolled and tested for malaria, helminths and anaemia at baseline, four, and eight months. Six hundred and ninety subjects were analysed in this study. Generalized linear mixed models were used to assess the relationship between infection status and Ascaris and Plasmodium parasite intensity on severity of anaemia, defined as a haemoglobin less than 11 g/dL.
RESULTS:
Malaria prevalence ranged from 35-78% over the course of this study. Of the malaria-infected children, 55% were co-infected with Ascaris at baseline, 60% were co-infected four months later and 48% were co-infected eight months later, underlining the persistent prevalence of malaria-nematode co-infections in this population. Over the course of the study the percentage of anaemic subjects in the population ranged between 84% at baseline and 77% at the eight-month time point. The odds of being anaemic were four to five times higher in children infected with malaria compared to those without malaria. Ascaris infection alone did not increase the odds of being anaemic, indicating that malaria was the main cause of anaemia in this population. There was no significant difference in the severity of anaemia between children singly infected with malaria and co-infected with malaria and Ascaris.
CONCLUSION:
In this cohort of Nigerian preschool children, malaria infection was the major contributor to anaemia status. Ascaris co-infection neither exacerbated nor ameliorated the severity of malarial anaemia.
PUBLISHED
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2262/727452013-01-01T00:00:00ZIgnoring discards biases the assessment of fisheries&apos; ecological fingerprint.http://hdl.handle.net/2262/72438
Ignoring discards biases the assessment of fisheries&apos; ecological fingerprint.
JACKSON, ANDREW
Understanding the pressures of fisheries on the ecosystem is crucial for effective management. Fishery removals, or catch, are composed of both landings and discards. However, the use of discards data in studies investigating the effect of the fishing pressures is sparse. Here, we explore the individual contribution of both these catch components to the overall pressure of fisheries on the ecosystem metrics. Using Irish observer data, we compare the linear relationship between several ecological metrics calculated for landings and discards with those of catch. Our results show that in fisheries with high discarding rates, discards can drive the fisheries’ ecological fingerprint and highlight the need to rectify landings-based estimates to make them representative of those of catch in order to gain a robust picture of the impact of fisheries.
PUBLISHED
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2262/724382013-01-01T00:00:00ZCooperation creates selection for tactical deception.http://hdl.handle.net/2262/72429
Cooperation creates selection for tactical deception.
JACKSON, ANDREW
Conditional social behaviours such as partner choice and reciprocity are held
to be key mechanisms facilitating the evolution of cooperation, particularly in
humans. Although how these mechanisms select for cooperation has been
explored extensively, their potential to select simultaneously for complex
cheating strategies has been largely overlooked. Tactical deception, the mis-
representation of the state of the world to another individual, may allow
cheaters to exploit conditional cooperation by tactically misrepresenting their
past actions and/or current intentions. Here we first use a simple game-
theoretic model to show that the evolution of cooperation can create selection
pressures favouring the evolution of tactical deception. This effect is driven by
deception weakening cheater detection in conditional cooperators, allowing
tactical deceivers to elicit cooperation at lower costs, while simple cheats are
recognized and discriminated against. We then provide support for our theor-
etical predictions using a comparative analysis of deception across primate
species. Our results suggest that the evolution of conditional strategies may,
in addition to promoting cooperation, select for astute cheating and associated
psychological abilities. Ultimately, our ability to convincingly lie to each other
may have evolved as a direct result of our cooperative nature.
PUBLISHED
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/2262/724292013-01-01T00:00:00Z